Center channel questions

"I don't want to buy a 5.1 channel system, just a mono amp being driven by a center channel decoder if such a thing exists."

I don't think such a thing exists, and if it did, there is a good possibility you would have a sync problem with the main speakers.

Does your main system have HT bypass capability?
 

I was in a similar situation...Initially I purchased a AVR to drive my center channel, but ended up purchasing rears. I use my preamp’s HT bypass when l’m watching television or movies. The AVR is turned off when I’m listening to 2-channel. Some would say my system is Highend and I thought this was the most economical way to improve the dialog when watching television and movies. 

It can be partly the speakers you are using, and partly lack of the center. A good center adds significant clarity.

I used to be on the "phantom center is good enough" camp, but after experimentation and research I am no longer. A center is noticeably better, and a neutral center is the best. :) Look for Monitor Audio as a solid affordable brand.

The only way you can "de-code" the center channel track is with an AVR. This would take the same space as a separate amp. However you would have 2 volumes to deal with, the 2 channel system and the AVR, this would become annoying. Unless your 2 channel preamp has unitygain. The other option is to not use the 2 channel system and buy a good sound bar, as mentioned above.

keis,

How are you getting the TV output to your system? What is the setup? Is it possible that you just have a setup problem. I know I had issues years ago when I tried to connect my cable box into my system via digital output. The cable box was set to Dolby Digital and I had to change it to PCM so it down-mixed the multi-channel audio down to 2 channels.

If your setup is good and you want a solution, perhaps a higher end under TV audio system like an upper-end ZVOX would work for you. It probably would be a self contained system, not using your existing L&R main speakers. But it would probably provide better dialog.

A more expensive choice would be to replace your current 2-channel pre-amp with a high-end multi-channel HT pre-amp and buy a center channel speaker and amp to power it. In the setup you would only set up the 3 speakers and set the rears/surrounds and sub to "none". However, this may diminish the sound quality of the 2-channel portion of your system unless you buy a super-high end multi-channel pre-amp.